Accurate step counter

Abstract

A device may obtain samples from an accelerometer and a gyroscope, determine kinematics signals based on the samples, and compute a number of steps taken by a user based on the kinematics signals.

1 . A method comprising:
 obtaining samples from an accelerometer and a gyroscope;   determining kinematics signals based on the samples; and   computing a number of steps taken by a user based on the kinematics signals.   
   
   
       2 . The method as in  claim 1 , wherein determining kinematics signals include:
 determining an acceleration signal, a velocity signal, or a distance signal.   
   
   
       3 . The method as in  claim 1 , further comprising:
 removing noise from the obtained samples.   
   
   
       4 . The method as in  claim 1 , further comprising:
 receiving an average step length from the user.   
   
   
       5 . The method as in  claim 4 , wherein computing a number of steps includes:
 computing the number of steps taken by the user based on the kinematics signals and the average step length.   
   
   
       6 . The method as in  claim 1 , wherein determining kinematics signals includes:
 numerically solving equations of motion to determine kinematics signals based on the samples.   
   
   
       7 . The method as in  claim 1 , further comprising:
 receiving samples from a Global Positioning System (GPS) receiver.   
   
   
       8 . The method as in  claim 7 , wherein determining kinematics signals includes:
 numerically solving equations of motion based on the samples that are obtained from the accelerometer, the gyroscope, and the GPS receiver.   
   
   
       9 . The method as in  claim 1 , further including:
 initializing the kinematics signals.   
   
   
       10 . A device comprising:
 an accelerometer for providing acceleration measurements;   a gyroscope for providing angular rate measurements; and   a processor to:
 accept the acceleration measurements from the accelerometer and the angular rate measurements from the gyroscope; 
 establish kinematics signals based on the acceleration measurements and the gyroscope measurements; and 
 count a number of user foot steps based on the kinematics signals and an average step length. 
   
   
   
       11 . The device as in  claim 10 , wherein the kinematics signals includes:
 a velocity signal, an acceleration signal, or a distance signal.   
   
   
       12 . A device comprising:
 a Global Positioning System (GPS) receiver for providing position measurements and velocity measurements;   an accelerometer for providing acceleration measurements;   a gyroscope for providing angular rate measurements; and   a processor to:
 accept the position measurements from the GPS receiver, the velocity measurements from the GPS receiver, the acceleration measurements from the accelerometer, and the angular rate measurements from the gyroscope; 
 establish kinematics signals based on the position measurements, the velocity measurements, the acceleration measurements, and the angular rate measurements; and 
 count user foot steps by comparing the kinematics signals and reference kinematics signals. 
   
   
   
       13 . The device as in  claim 12 , wherein the kinematics signals include:
 a velocity signal, a acceleration signal, or a distance signal.   
   
   
       14 . A device comprising:
 means for detecting acceleration in a first coordinate frame;   means for detecting angular rates in the first coordinate frame;   means for determining kinematics signals in a second coordinate frame based on the detected acceleration and the detected angular rates; and   means for counting steps based on the kinematics signals.   
   
   
       15 . The device as in  claim 14 , wherein the kinematics signals includes:
 an acceleration signal, a velocity signal, or a distance signal in three dimensions.   
   
   
       16 . The device as in  claim 14 , further comprising:
 means for removing noise from the detected acceleration.   
   
   
       17 . The device as in  claim 14 , further comprising:
 means for receiving an average step length from a user that is carrying the device.   
   
   
       18 . The device as in  claim 17 , wherein the means for counting steps includes:
 means for counting steps taken by the user based on the kinematics signals and the average step length.   
   
   
       19 . The device as  claim 14 , further comprising:
 means for solving equations of motion to determine the kinematics signals based on the detected acceleration and the detected angular rates.   
   
   
       20 . A portable device comprising:
 an accelerometer for providing acceleration measurements;   a gyroscope for providing angular rate measurements;   a processor to:
 accept the acceleration measurements from the accelerometer and the angular rate measurements from the gyroscope; 
 establish kinematics signals based on the acceleration measurements and the gyroscope measurements by solving equations of motions; and 
 measure a distance traveled based on the kinematics signals; and 
   a housing that contains components of the portable device, the components including the accelerometer, the gyroscope, and the processor.   
   
   
       21 . The portable device as in  claim 20 , wherein the housing includes a cell phone housing, a laptop housing, an electronic notepad housing, or a personal digital assistant (PDA) housing, a pager housing, or a mobile telephone housing.